The present invention relates to the art of rotary air locks and, more particularly, to a method and means for removing any particulate material resting on the end of a vane before it comes into pressure sealing relationship with its sealing land.
The invention is particularly applicable to rotary air locks for feeding metallic chips into a pressurized chamber or pressurized pneumatic conveyor tube and will be described with particular reference thereto although it will be appreciated that the invention has other applications.
Rotary air locks of the type to which this invention pertains are generally comprised of a housing having an upwardly facing inlet opening and a downwardly facing outlet opening. A vaned rotor in the housing successively opens pockets between the vanes to the inlet opening where the granular material falls into the pocket under the force of gravity and then as the rotor turns, opens the pocket to the outlet opening, where the material falls by gravity into the pressurized chamber. Intermediate the inlet and outlet openings, the vane ends pass in close spaced sealing relationship with leading and trailing lands formed on the inside of the housing.
In the past difficulty has been experienced with granular material remaining on the vane ends as the vane ends come into sealing relationship with the leading land. This is particularly so when metallic chips, which are sometimes long and curly, are being handled because the chips themselves will not only rest on top of the vane ends but will also curl over the leading face of the vanes adjacent the outer edge. In such instances, the chips are not wiped off by the leading edge of the land surface and are forced between the vane ends and the land surface resulting in excessive and undesirable wear thereto.